Fix clippy lints for rust 1.62 (#3300)

## Issue Addressed

Fixes some new clippy lints after the last rust release
### Lints fixed for the curious:
- [cast_abs_to_unsigned](https://rust-lang.github.io/rust-clippy/master/index.html#cast_abs_to_unsigned)
- [map_identity](https://rust-lang.github.io/rust-clippy/master/index.html#map_identity) 
- [let_unit_value](https://rust-lang.github.io/rust-clippy/master/index.html#let_unit_value)
- [crate_in_macro_def](https://rust-lang.github.io/rust-clippy/master/index.html#crate_in_macro_def) 
- [extra_unused_lifetimes](https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_lifetimes)
- [format_push_string](https://rust-lang.github.io/rust-clippy/master/index.html#format_push_string)

consensus/proto_array/src/fork_choice_test_definition.rs

@@ -105,7 +105,6 @@ impl ForkChoiceTestDefinition {
                             Hash256::zero(),
                             &spec,
                         )
-                        .map_err(|e| e)
                         .unwrap_or_else(|e| {
                             panic!("find_head op at index {} returned error {}", op_index, e)
                         });
@@ -132,7 +131,6 @@ impl ForkChoiceTestDefinition {
                             proposer_boost_root,
                             &spec,
                         )
-                        .map_err(|e| e)
                         .unwrap_or_else(|e| {
                             panic!("find_head op at index {} returned error {}", op_index, e)
                         });

consensus/proto_array/src/proto_array.rs

@@ -240,7 +240,7 @@ impl ProtoArray {
                 // not exist.
                 node.weight = node
                     .weight
-                    .checked_sub(node_delta.abs() as u64)
+                    .checked_sub(node_delta.unsigned_abs())
                     .ok_or(Error::DeltaOverflow(node_index))?;
             } else {
                 node.weight = node